Angiostatin Down-Regulates Vascular Endotheial Growth Factor Expression In Human Tongue Squamous Cell Carcinoma Cells

Objective angiogenesis plays a critical role in tumor growth and tumor metastais, Angiostatin(AS) is one of the known the strongest angiogenesis inhibitors while vascular endothelial growth factor(VEGF) is the most important angiogenesis activator,the link between AS and VEGF in human tongue squamous cell carcinoma has never been reported.The purpose of these experiments is to evaluate the effect of angiostatin on va-scular endothelial growth factor expression in human tongue squamous cell carcinoma cells.Methods Human tongue squamous cell carcinoma (Tca8113) cell line was cultured and subcultured according to routine.cells of the sixth generation during the cell growth period were collected and BALB/C nude mice,6 weeks of age,received s.c. injections of 2×106 tumor cells suspended in 100μl of PBS in the proximal dorsum. then eighteen mice were randomly divided into three groups (6 mice each): the PBS group in- jected with PBS, the AS(250ng) group injected with 250ng purified angiostatin,and the AS(30μg) group in - jected with 30μg purified angiostatin . reagents were injected intraperitoneally twice daily and tumor vo- lume was calculated twice weekly for 21 days ,then animals were sacrificed and After surgical resection each tumor specimen was divided into two parts. The first part was submitted to both Immunocytochemistry for VEGF,VEGFR1,VEGFR2 and CD34,and TUNEL apoptosis assay. The second part was prepared for Semi-Quantitative RT-PCR Analysis of VEGF,VEGFR1 and VEGFR2 mRNA Abundance.Results in the AS(250ng) group and the AS(30μg) group,there was an increase in apoptotic index (AI) (P<0.05) and there was a decrease in Protein and mRNA expression levels of VEGF,VEGFR1 and VEGFR2,in tumor volume and in MVD(tumor angiogenesis was estimated by determining microvessel density with the use of CD34 antibody) (P<0.05). These changes were more obvious in the the AS(30μg) group than in the AS(250ng) group(P<0.05).Conclusion AS down-regulates VEGF expression in human tongue squamous cell carcinoma cells in a dose-dependent fasion。(in addition,AS leads to a growth and angiogenesis suppression and promotes apoptosis and down-regulates VEGFR1 and VEGFR2 in human tongue squamous cell carcinoma in a dose-dependent fasion。)...